I think that we can all see that this is true. People have changed for the worse within my lifetime(I'm 51). When I was a kid, obesity was rare, even in adults, it was not the norm. There was no adhd add, people getting diagnosed with this and that form of rare and common cancer right and left, etc etc etc.
But much of the story is being left out. For example when we were kids we had fun by going out and climbing trees, running, frisbee, etc. We were active. Now a days kids spend most of their time indoors playing video games, or they are on computer or getting the majority of their exercise by texting their friends 300 times a day. And conditions like ADHD to me are simply syndromes being made up to push more drugs. Just like how obesity had its definition changed to a disease so drugs could be legally prescribed for the condition and unapproved claims for supplements can be suppressed since you cannot make claims for disease cures.